Attempts are being made to develop a model in which behavioral aspects of ethanol dependence can be investigated in rhesus monkeys. To induce voluntary oral intake of pharmacologically significant quantities of ethanol, a conditioning procedure is used in which the temporal delay between ingestion of drug and onset of effects is reduced. Catheterized monkeys are intravenously infused with an ethanol solution each time a response is made for oral ethanol. In addition to this temporal pairing, the dose of ethanol per response is gradually partitioned between the oral and i.v. routes such that the i.v. portion of the dose decreases as the oral portion increases. This allows for gradual adaptation to the apparently noxious taste of the ethanol. At the end of this partitioning period, the entire dose (0.1 g/kg/response) is delivered orally. The animal is then offered a free choice between water and 18% ethanol. Preliminary evidence suggests that this procedure is successful in inducing ethanol intake significantly above control levels in some animals. The second major aspect of this project is the continued investigation of the development of physical dependence to ethanol in rhesus monkeys. Studies are currently directed toward the development of procedures to quantitatively evaluate the withdrawal severity. Physiological tremor was chosen as the parameter to measure, since increased tremor is one of the earliest and most universal symptoms of ethanol withdrawal. These procedures, if sufficiently reliable and sensitive, will be used in subsequent experiments as bases for comparing the effects of the dose-time variables as well as differeet patterns of ethanol administration (e.g. constant vs. fluctuating blood ethanol concentrations) on withdrawal severity.